The salicylate hydroxylase, a flavoprotein monooxygenase, catalyzes the decarboxylative hydroxylation of salicylate to form catechol. Nucleotide sequence of a salicylate hydroxylase gene and its 5'-flanking region in chromosomal DNA of Pseudomonas putida KF715 was analyzed. The salicylate hydroxylase was encoded in an open reading frame with 1308 base pairs which can encode a polypeptide of molecular weight 48 kDa with 435 amino acids. The open reading frame was preceded by a putative ribosome-binding sequence. A predicted amino acid sequence of the salicylate hydroxylase exhibited 84% identity with corresponding enzyme encoded in NAH7 plasmid, and 20 to 30% homologies with other similar flavoprotein monooxygenases. A 5'-flanking sequence of the salicylate hydroxylase gene exhibited extensive homology with promoter and nahR-binding site of sal operon in NAH7 plasmid.